Temporal dynamics of soil nematode community structure at the depth of 0 - 30 cm was compared under invasive Ambrosia trifida and native Chenopodium serotinum in an abandoned cropland in Northeast China.

Gynomonoecy in Chenopodium quinoa (Chenopodiaceae): variation in inflorescence and floral types in some accessions

A virus was isolated from the orchid Cattleya in Hainan,through sap inoculiation on Chenopodium amaranticolor, an indicator plant,Single lesion inoculation was made on Tetragonia expansa more than three times,Thevirus was purified with the procedure including PEG precipitation and diff-erential centrifugation. Its rod-shape particles could be specifically decor-dted in IEM test by the antiserum against Odontoglossum ringspot virus(ORSV), ELISA and Ouchterlony double diffusion assay reveal that thevirus...

A virus was isolated from the orchid Cattleya in Hainan,through sap inoculiation on Chenopodium amaranticolor, an indicator plant,Single lesion inoculation was made on Tetragonia expansa more than three times,Thevirus was purified with the procedure including PEG precipitation and diff-erential centrifugation. Its rod-shape particles could be specifically decor-dted in IEM test by the antiserum against Odontoglossum ringspot virus(ORSV), ELISA and Ouchterlony double diffusion assay reveal that thevirus isolated from the orchid was serologically closely related to ORSVand homologously partially related to Tobacco mosaic virus(TMV),SDS PAGE shows that the coat protein of the virion consisted of only one sub-unit with the molecular weight of 17.3KD,and nucleic acid electrophoresison agarose gel displayed one band which possessed similar molecular weightto the RNA of TMy. These biological,seroiogical and biochemical propertiesof the virus isolated suggested that it should be ORSV belonging to Toba-moviruses. ORSV has been one of the two most prevalent viruses infecting nearly all kinds of orchid cultivars and vanilla worldwide. For the purposeof providing a virus detection method for orchid growers,we prepared a specific antiserum by immunizing rabbits with the purified virus and madedetection on some diseased orchids by using SPA ELISA.

Citrus tatter leaf virus(CTLV)was mechanically transmitted to 23 herbaceousspecies from eight families. It induced local lesion on Vigna sinensis, systemic yellow spotand distortion on Chenopodium quinoa and C. amaranticolor. local spot or Celosia cristataand systemic light mottle on Nicotiana celevilandii. It was also back transmitted fromN. celevilandii to Citrus reficulata,C, citrange and caused typical "tatter leaf "symptoms.DEP for this virus was 10-5, when tested from infected leaf sap of C. reticulata....

Citrus tatter leaf virus(CTLV)was mechanically transmitted to 23 herbaceousspecies from eight families. It induced local lesion on Vigna sinensis, systemic yellow spotand distortion on Chenopodium quinoa and C. amaranticolor. local spot or Celosia cristataand systemic light mottle on Nicotiana celevilandii. It was also back transmitted fromN. celevilandii to Citrus reficulata,C, citrange and caused typical "tatter leaf "symptoms.DEP for this virus was 10-5, when tested from infected leaf sap of C. reticulata. Virusparticles that characterized as Capiloviruses were detected under electron microscopefrom leaf-sap of diseased hosts above. Herbaceous species can be used as indicators forthis virus. Virus crystallized bodies were found in phloem cells of C. reticulata anc C.citrange infected with CTLV, the same structures were also observed in mesophyll cellsof Chenopodium quinoa and N. clevilandii infected with CTLV. but the crystallizationbodies were looser aggregated and smaller. Degradation of reticulum and accumulating ofstarch bodies was observed on chloroplasts of infected mesophyll cells of above hosts.This is the first report of cytopathological characteristics of this virus disease. Positiveserological relationship was found between CTLV and apple stem grooving virus( ASGV) by agar double diffusion test and ISEM. This indicated the possibility for usingASGV antibodies to detect CTLV in plant materials.

Two virus, isolates,P-935 and B-934 ,were obtained from diseased Pisum sativum and Vicia faba,and 14 plant species in 6 families were mechanically inoculated by the isolates.Among the tested plants,P-935 could infect 13 species and B-934 infected 14 species. The two isolates pro-duced similar symptoms on these plants,except for symptoms on Phaseolus vulgaris.The two Iso-lates were easily transmitted by Myzus persicae in a nonpersistent manner.P-935 and B-934 were purified form Chenopodium quinoa by a method...

Two virus, isolates,P-935 and B-934 ,were obtained from diseased Pisum sativum and Vicia faba,and 14 plant species in 6 families were mechanically inoculated by the isolates.Among the tested plants,P-935 could infect 13 species and B-934 infected 14 species. The two isolates pro-duced similar symptoms on these plants,except for symptoms on Phaseolus vulgaris.The two Iso-lates were easily transmitted by Myzus persicae in a nonpersistent manner.P-935 and B-934 were purified form Chenopodium quinoa by a method that yielded up to 147 mg/kg and 1 28 mg/kg tis-sue,respectively. Purified preparation of two isolates contained isometric particles ca. 25 nm in di-ameter,The capsid protein contained two polypeptides with molecular weight of 42.5 kD and 21.2 kD. Amorphous inclusions with membrane accumulations were found in the cytoplasm of infected Pisum sativum leaf tissue. In agarose gel diffusion tests,P-935 and B-934 strongly reacted with the antisera of BBWV serotype Ⅱ.On the bases of these characteristics,P-935 and B-934 were identi-fied as broad bean wilt virus(serotype Ⅱ).Field survey in Hangzhou surburb showed viral dis-eases were severe in Pisum sativum and Vicia faba.